1. Department of Pathology, Tachikawa General Hospital, Nagaoka, Niigata, Japan
2. Histopathology Core Facility, Niigata University Faculty of Medicine, Niigata City, Niigata, Japan
3. Department of Radiology, Tachikawa General Hospital, Nagaoka, Niigata, Japan
4. Department of Gastroenterology, Tachikawa General Hospital, Nagaoka, Niigata, Japan
5. Department of Gastrointestinal Surgery, Tachikawa General Hospital, Nagaoka, Niigata, Japan
6. Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, USA